1. Field of the Invention
The present invention relates to a liquid crystal display, and more particularly, to a liquid crystal display, which can make workability easier and reduce assembly cost by connecting lamps to an external power supply.
2. Discussion of the Related Art
In general, the application scope of a liquid crystal display device has been broadening due to it characteristics of light weight, thin profile, and low power consumption. LCD devices are now used in office automation equipment, audio/video equipment, and so forth.
A liquid crystal display device includes a plurality of control switches arranged in a matrix and controls the amount of light being transmitted in accordance with a signal applied to the control switches, thereby generating a desired image. Because the liquid crystal display device is not a self luminous display device, it requires a separate light source, such as a backlight unit.
A backlight unit may be generally classified as a direct type and an edge type in accordance with the location of a light source. The edge type backlight unit has a light source along one side of a liquid crystal display device, and irradiates light from the light source to a liquid crystal panel through a light guide plate and a plurality of optical sheets. The direct type backlight unit has a plurality of light sources disposed directly under a liquid crystal panel, and irradiates light from the light sources to the liquid crystal panel through a diffusion plate and a plurality of optical sheets. Recently, the direct type backlight unit is more often used because it has improved brightness, more consistent light uniformity and better color purity, as compared to the edge type backlight.
A cold cathode fluorescent lamp (hereinafter, referred to as “CCFL”) and an external electrode fluorescent lamp (hereinafter, referred to as “EEFL”) are mainly used as a light source of a backlight unit. As an EEFL has its electrodes exposed at the exterior thereof, EEFLs can be driven in parallel more easily compared to a CCFL in which electrodes are inserted into a glass tube.
FIG. 1 shows a related art method for connecting lamps and an external power supply in a direct type LCD. The lamps are implemented in EEFLs, and the electrodes 1 of the lamps are elastically pressed against conductive clips 2 and electrically connected to a common electrode 4 secured on a common board 3. And, the electrodes of the lamps 1 are supported and fixed by a side support 5. The common board 3 is a molded object made of plastic and supported by a bottom cover 9. A lamp wire 9 connects the common electrode 4 and an inverter (not shown) to each other to transmit a lamp driving power generated from the inverter to the common electrode 4.
The connection method shown in FIG. 1 is advantageous in terms of safety, but has low assemblability because screw fastening 6 and spot welding 7 are required when connecting the lamp wire 8 to the common electrode 4. Moreover, this method is not compatible with a recently proposed IPB (Integrated Power Board) Model. The IPB model has, an inverter, which has been separately provided in the conventional art, integrated in the power board of a system to make LCDs slimmer and make assembling convenient. Therefore, if the assembling of a liquid crystal module without an inverter is completed by a module manufacturing company, a set manufacturer assembles an integrated power board to the liquid crystal module to supply lamp driving power to lamps. In such an IPB model, an integrated power board and lamps are electrically connected by pin connector connection in order to make assembling simple. However, the connection method as shown in FIG. 1 does not allow for connector connection, thereby lowering model compatibility.